Most electricity is produced at a power plant. When the electricity leaves the power plant, it is sent over high power transmission lines. Because electricity loses some of its strength, i.e., voltage, as it travels, it may be helped along to its destination by a transformer which will increase (i.e., step up) the voltage that it receives.
When the electricity gets closer to where it will be consumed, another transformer will be utilized to decrease (i.e., step down) the voltage that it receives before forwarding to a consumer.
Difficulty arises when a transformer at a substation along the distribution path from the power plant to the consumer breaks down. When a failure occurs a replacement/spare transformer is utilized to restore power. However, the replacement transformer has to meet the design requirements of the substation in need.
A transformer is typically designed to accommodate the layout of a particular substation. The layout from one substation to another will vary according to the electrical connections required to connect the transformer to a supply and a load. The electrical connections to the supply and the load may be via a delta connection or a wye connection. Accordingly, there are four connection configuration combinations i.e., a delta-delta, a wye-wye, a delta-wye, or a wye-delta that a substation in need could require to connect the transformer to a supply and, respectively a load.
Whether a transformer operates as a step up transformer or a step down transformer may also vary from one substation to another, and thus, the output voltage required from a transformer may also vary from one substation to another. Transformers have been developed to accommodate various supply and load connection configurations or various output voltage requirements. However, a transformer that has circuitry that allows a user flexibility in selecting both the supply and load connection configurations and the desired output voltage is desirable.
Because of the various possible supply and load connection configurations, and the various possible output voltages that a substation may require, it is costly for an electric company to maintain a replacement transformer for every possible transformer configuration. Typically, electric companies maintain transformers in inventory for utilization as replacement transformers. However, a transformer design is often unique, and thus, a transformer may not be available that is compatible with the specific requirements of the substation in need. As a result, a power outage is often extended until a suitable replacement is found.
Accordingly, there is a need for a spare transformer that is user-configurable to accommodate four supply and load connection configurations, and multiple output voltages.